模块化多维直线运动机电平台

在光机产品中,调焦是最基本的功能之一,而调焦运动往往通过直线位移运动去实现。当光学系统涉及到多方向调焦时,就需要多维直线运动平台作为实现机构。论文提出一种模块化多维直线运动机电平台,通过电机、丝杠、直线导轨和滑块等电气组件和机械元件组成一维直线运动平台,并将一维运动平台模块化,通过滑块和底座一体化形成二维,进而形成三维移动机电平台,去实现多维度的直线位移运动,从而实现多维度的光机系统的调焦。     

一种两轴限位的一维转台设计及应用

为了实现测量功能,需要天线在水平、垂直两个方向进行高频运动,模拟振动的信号源,采集天线在振动峰值的信号。文中设计为一维转台,用平面旋转运动代替水平、垂直方向的直线运动,从而避免两向运动的耦合问题以及高频运动的驱动问题。     

铣削加工

<正>铣削加工是应用相切法成形原理,用多刃回转体刀具在铣床上对平面、台阶面、沟槽、成形表面、型腔表面、螺旋表面进行加工的一种切削加工方法。它是目前应用最广泛的加工方法之一。铣削加工时,铣刀的旋转是主运动,铣刀或工件沿坐标方向的直线运动或回转运动是进给运动。不同坐标方向运动的配合联动和不同形状刀具相配合,可以实现不同类型表面的加工。     

中小批量偏心凸轮的数控车削加工

在机械传动中,回转运动变为往复直线运动或直线运动变为回转运动,一般都用凸轮机构来完成,如柱塞泵凸轮。介绍在经济型数控车床上,依托三爪自定心卡盘,设计一套简单的夹具,实现批量加工不同偏心距离的凸轮。     

龙门式上肢偏瘫康复训练机器人

介绍一种龙门式上肢偏瘫康复训练机器人,包括:水平左右运动机构、水平前后运动机构和竖直上下运动机构。可以带动患者手部作水平左右、水平前后和竖直上下三个方向的直线运动,同时,手柄组件具有三个旋转轴正交的被动旋转自由度,通过三个方向的直线运动和三个旋转轴正交的旋转运动可以合成出任意复杂的上肢动作,从而使患者上肢各关节、运动肌肉群以及运动功能神经系统群得到有效的物理刺激,达到恢复患者上肢运动功能的目的。本康复训练机器人的特点在于采用龙门直角坐标的结构形式,扩大了患者上肢的运动范围,同时三个方向的直线自由度不存在运动耦合,便于实现复杂的轨迹规划与控制。     

新的运动变换机构——日本第20届全国发明技巧表演会得奖项目

把直线运动变成回转运动有各种各样的变换方法,一般被人熟知的有曲轴和齿轮齿条机构。但是前者不能改变行程,而且还产生很复杂的振动。后者由于回转方向是变化的,难以用人的手脚来把往复直线运动变换成不改变回转方向的连续回转运动。     

精密机床直线运动误差在线检测中的数学模型与参数选择

一、引言机床直线运动误差对机加工性能的影响很大。因而寻求一种实时测量机床直线运动误差的方法,以便进行补偿加工,提高工件质量是非常必要和重要的。在此方面,近年来国内外已开展了一些工作,主要是采用三点法的测量原理及误差分离技术,但在数学模型的建立方面尚存在不足,参数选择亦未见有发表。本文仅就这两方面作一探讨。二、测量原理与数学模型当运动部件沿直线导轨运动时直线误差可分为互相垂直且又和运动方向垂直的二个分量,一般其中只有一个分量为误差敏感量。现以分析水平面内垂直于运动方向x轴的y方向误差为例,由于我们总是借助于工件或直尺进行测量,因此用三点法测量时A、B、C三个传感     

液压 第三讲 油缸和油马达

在液压系统中,将液压能转变为机械能的执行机构统称为液动机。油缸和油马达就是这样的液动机。一、油缸有什么用?在液压驱动的机械中,直线运动和摆动运动是由油缸来实现的。因为实现这些运动时,油缸结构最简单,效率最高。有些液压传动机械,它们的执行元件甚至全部是油缸。如汽车上制动用的刹车油缸、液压起重机改变臂架角度的变幅油缸及飞机上的起落架油缸等等,其应用是最广泛的。二、油缸有哪些类型?油缸的种类繁多,按照运动型式可分成直线运动和摆动运动。直线运动的油缸又可分为     

机床精度检验方法讲座——第三讲 机床直线运动精度的检验方法

关于机床运动件直线运动精度的检验,在我国机床精度标准中早已有一些规定。如:检验“工作台运动在垂直平面内的不直度”、“工作台运动时的倾斜”等……,但是,一从未对直线运动精度的概念作过系统的说明。在实际中,也常把直线运动精度的检验与导轨直线度检验混为一谈。为了便于了解运动件直线运动精度的检验方法,我们将国际上多种现行的有关直线运动精度的概念作一些归纳,尽量系统地加以说明,并介绍一些常用的检验方法。 一、直线运动精度的概念 1.运动件的直线运动 当分析一个刚体在直角座标系中运动时,可以把这个运动看成由下面几个简单的…     

偏心轴套的加工

在机械传动中,要使回转运动转变为直线运动,或由直线运动转变为回转运动,一般采用曲柄滑块（连杆）机构来实现,这些机构基本上是偏心轴、偏心套,一般非常难加工。文中重点介绍了它们的加工方法,并给出了加工实例。     

Schedule efficiency in a robotic production cell

In this paper, we analyze the efficiency of a given robot movement schedule for the case of a flow shop robotic production cell withm different machines, one input conveyor, and one output conveyor. We begin with the case of one-robot cells and extend our results to multirobot cells. The paper studies the efficiency of a movement schedule for identical parts by defining a movement network associated with this schedule. This network models any cell layout and applies to multirobot cells. Using the movement network, we propose two cycle time evaluation methods, the first using linear programming and the second based on finding a longest path. The latter method generates a procedure to obtain an analytical formula for the cycle time. We extend the proposed methods to study the efficiency of a given input sequence (schedule) for different parts, that is, to determine the sequence processing time. The results obtained here allow us to quickly evaluate the efficiency of any given feasible movement schedule, for identical or different parts.     

一种积分时间可调型线阵CCD的改进驱动方案

为了提高积分时间可调型线阵CCD的时序调整灵活性和驱动程序的可移植性。根据积分时间可调型线阵CCD芯片的工作原理,在光积分栅电极脉冲的低电平区附近,对转移栅脉冲的时序加以改进,提出了一种新的驱动时序设计方案。程序设计语言使用了硬件描述语言Verilog,采用Modelsim软件对东芝公司的TCD1304AP时序方案进行了功能仿真,并针对ALTERA公司的EPM240T100C8N芯片进行了适配。仿真结果和硬件实验结果表明该方案正确,其具有可控性好、可移植性好、开发效率高的特点。     

GRNN-PSO视角下的网络安全势态预测研究

网络安全态势预测是属于网络安全态势最为关键构成部分之一,在对网络安全预防制订决策面发挥着非常重要作用。针对网络安全态势预测存在误差等方面问题,本文提出一种GRNN-PSO(改进广义回归神经网络)预测方法,其目的就是使得网络安全态势预估的精准度得到改善。运用时间窗口移动的方法,将各个离散时间监测点的网络安全态势值形成部分线性相关的多元回归数据序列,把它可以看作为样本集录进改进广义回归神经网络中再进行训练,从而形成相关预测模型。在改进广义回归神经网络对其进行训练之中,运用粒子群算法动态地搜索广义回归神经网络最优培训参数,使得选择广义回归神经网络训练参数等方面难题得到解决,最后通过对传统预测方法与改进过的广义回归神经网络预测方法进行相关实验,实验结果体现了前者比后者的方法具有更佳的性能。     

Fault diagnosis and protection of motors in coal shearer

Symmetrical components method is employed in analysis of the characteristic motor faults.Motor protection method is put forward based on detecting positive sequence,negative sequence and zero sequence current.And problems of lack of motor overload capacity in existing mining motor protection system,impact of dynamic current on stage and definite-time delay operation and inaccuracy of criterion phase failure protection are analyzed.The unbalanced faults protection and inverse-time overload protection,which can make protection time change with the current movement,are proposed.The above problems can be solved,and the reliability and intelligent of coal shearer are improved.     

A rule-based frame system for concurrent assembly machines

The aim of this research is to develop a rule-based frame system for printed circuit board (PCB) assembly to generate the component feeder arrangement and placement sequence for concurrent chip placement machines. A knowledge base of frames, assertions and rules are used in the methodology to solve the PCB assembly process of SMT components. The system has been implemented using an AI programming environment, GOLDWORKS^®. A heuristic approach is used to minimize placement cycle time in PCB assembly. The objective of the solution method is to reduce theX-Y table displacement, movement and component feeder translation movement. Such a system is aimed at obtaining good solutions to the problem as illustrated by an example.     

Solutions of nonlinear constrained optimal control problems using quasilinearization and variational pseudospectral methods

An alternative method for nonlinear constrained optimal control problems is developed in this paper. The proposed method converts the nonlinear optimal control problem into a sequence of constrained linear quadratic (LQ) optimal control problems using quasilinearization methods. And then we present a variational pseudospectral method based on dual variational principles and pseudospectral approximations in order to transform the constrained LQ problem into standard linear complementary problems (LCPs) which can be solved easily. The proposed method is highly efficient due to the benefits of qualsilineaization techniques and the sparse and symmetric properties of coefficient matrixes obtained by variational principles. And solutions of high precisions can be obtained with few time nodes and boundary conditions can be prescribed because of pseudospectral approximations. Besides, extra costate estimations are not required simply because this method is constructed by dual variational principles. Several numerical examples are simulated and comparisons between different methods are offered to demonstrate effectiveness and advantages of the proposed method.     

Networked control of industrial automation systems—a new predictive method

A new method for real-time prediction of uncertain network transmission time delays and a method for closed-loop control of manufacturing and industrial plants through networks are introduced. The proposed delay prediction method is based on the multilayer perceptron neural model. In order to minimize the number of neurons in the first layer of the network and hence reducing the computational burden in a real-time implementation, a method for determination of the Markov order of the time delay sequence is presented. Using the predicted delay, and a zero-order hold equivalent discrete-time model of the plant, a time varying state feedback control algorithm with a real-time gain updating strategy is proposed. A sufficient condition for closed-loop stability is also derived using the switching theorem for linear systems. The proposed method is shown, through two industrial networked case studies, namely, a DC motor driving a transportation roller for paper sheets and a milling machine. Simulation studies depict the efficacy of the proposed method in controlling such challenging problems.     

压缩机网状阀悬臂式弹簧的计算

建立压缩机网状阀悬臂式弹簧物理模型,分析悬臂式弹簧刚度特性、运动等效质量及应力。通过分析网状阀工作过程可知,当悬臂式弹簧变形大于其临界变形时,刚度特性由线性变为非线性,线性区与非线性区的刚度需分别计算。运用瑞利法分析悬臂式弹簧的运动等效质量,用于模拟气阀运动规律。运用第三强度理论对悬臂式弹簧所受应力进行分析,用于指导其可靠性设计。     

Image sequence filtering algorithms for resolution improvement in applicative noise conditions

Algorithms for improving the resolution of a sequence of images distorted by applicative noise manifested in the form of randomly shaped local regions of occlusion are synthesized and analyzed. The basis is the implementation of an optimal linear filtering algorithm in block form, which is synthesized with account for possible emergence of false observations in individual elements of the analyzed images. A method for incorporating the results of independent segmentation of each individual image into the recursive filtering process is proposed, which enhances the quality of the final processing.     

A one-dimensional theoretical prediction of the effect of reduced end-plate permeability on the mechanics of the intervertebral disc

The permeability of the cartilage end-plate (CEP) may play an important role in intervertebral disc (IVD) degeneration by controlling the convective and diffusive transport of metabolites into the nucleus pulposus. A one-dimensional poroelastic model was used to predict the effect of a CEP of lower permeability than the disc tissue on the convective transfer into and out of the IVD. With decreasing CEP permeability, associated with degeneration, the model predicted that the change in disc height with time became more linear; the disc could not rehydrate as quickly; and internal fluid movement was slowed. This study has shown that CEP permeability will only markedly have an effect on fluid movement, and hence convective nutrition, if the permeability of the CEP is reduced to less than that of the disc tissue.